What's the usual mark people get for SPA? I heard that the mark is often overestimated.
Originally posted by Thomas00:Guys, how come Q22 not C.
i still don't get Q11- wouldn't increasing Fe3+ conc mean POE shifts right meaning that there's decreased oxid so Eoxid becomes less negative? so Ecell becomes more positive? @_@
i think bc you want only 1 full product, so your original atoms from PtCl4 must all be there.
Originally posted by Thomas00:Ah i see, thanks.
For Qn 11,
Ag+ is reduced, Fe2+ oxidised.
Ecell = Red - Oxid
= 0.80-0.77
U want to make it 0, so have to increase 0.77 to 0.80, so increase Fe3+ can increase 0.77V to 0.80V.
It's because not all the cl will be removed. so it forms pt (nh3)4cl2 which form ionic bonds with 2 chloride ions Qn 7 I got 114. Anyone can show me how to get 117?
Why is the oxidation state of Vanadium not +4?
Originally posted by captainkidzs:It's because not all the cl will be removed. so it forms pt (nh3)4cl2 which form ionic bonds with 2 chloride ions Qn 7 I got 114. Anyone can show me how to get 117?
I suspect you used 76cm^3 instead of 78cm^3.
EDIT: Thanks @HardcoreBubbles for pointing out typo. You used 78cm^3 instead of 76cm^3.
@ Thomas because not all chlorine will be removed. so it should form pt (nh3)4cl2 which goes on to form ionic bonds with 2 chloride ions.
I got option B for qn 7.
@sky because if u look at the data booklet, the product is the reactants for the reaction just above it. and Eo is still positive so it should form v2+
Originally posted by captainkidzs:
DemonicTable mixed it up: you used 78 instead of 76. Initial reading was 2!
but don't u need to consider that the initial reading was 2? and the liquid should be 76 since u subtract the difference to get the amount of liquid
Originally posted by HardcoreBubbles:i still don't get Q11- wouldn't increasing Fe3+ conc mean POE shifts right meaning that there's decreased oxid so Eoxid becomes less negative? so Ecell becomes more positive? @_@
i think bc you want only 1 full product, so your original atoms from PtCl4 must all be there.
By looking at Fe3+ + e -> Fe2+
Increase in Fe3+ will cause +0.77V to become more positive.
Then you factor in the equation
Ecell = Ered - Eoxd
Original Ecell = +0.80V - (+0.77V)
New Ecell [After adding Fe3+] = +0.80V-(+0.80V) = 0
I'm not sure if this is the right explanation, but thats how i do it :)
Hi i made careless mistakes and got 26. Will there be any chance to get an A or even a B if my p2 was ok and my p3 was good?
sorry I made a careless mistake and keyed in 78 ><
Originally posted by Thomas00:By looking at Fe3+ + e -> Fe2+
Increase in Fe3+ will cause +0.77V to become more positive.
Then you factor in the equation
Ecell = Ered - Eoxd
Original Ecell = +0.80V - (+0.77V)
New Ecell [After adding Fe3+] = +0.80V-(+0.80V) = 0
I'm not sure if this is the right explanation, but thats how i do it :)
Ahh I see! Thank you :)
I got a 37 haha. Wanted to change my answer to B from C for the Pt question as I realized last min but ran out of time :(...
@captainkidz that's exactly why you should get C not B haha. did you miscalculate?
I keyed in to the gc wrongly haiz
Originally posted by Taengu:Hi i made careless mistakes and got 26. Will there be any chance to get an A or even a B if my p2 was ok and my p3 was good?
Sure, have to see your SPA and the bell curve. Theres always a chance!
sorry 23 is B typo
Originally posted by Taengu:Hi i made careless mistakes and got 26. Will there be any chance to get an A or even a B if my p2 was ok and my p3 was good?
Well it's quite possible. My friend he got 27 for mcq last year but he got a B. So it really depends on other components and of course the bell curve
But A is not possible with that kind of mcq score right? Btw what uni course are you guys planning on taking? @captain did ur friend score well in normal exams?
if assuming all your papers are A, then i would assume a 75% for mcq is good enough.
even if they bell curve they cannot curve it up too much
like cambridge said, as long as you hit the required standard, as long as you hit the required standard.
dont worry if everyone around you is getting 37 i've heard multiple 40s with this paper lol (tbh no need to memorise) but A isnt 100 or 90%
Normally he gets C in sch. Don't worry so much. If u have more papers to go just focus on it.
hi just asking how do you derive at C for qn 13? my answer was A
Originally posted by captainkidzs:Normally he gets C in sch. Don't worry so much. If u have more papers to go just focus on it.
yeah thereafter then think about how to survive the 24km route march in tekong
wah i think i got 32 or 33.... ugh fml
I am already 1 year into army, been through all those. Now in unit. 1 year more to ord.Guys who finish jc make sure go enjoy your free time. Otherwise u will regret in army
Originally posted by notamugger:hi just asking how do you derive at C for qn 13? my answer was A
U never x2 the X value u found from the KSP of ZnF2
Anyone sure of the answer for Question 4? isit D or A?
Def D. Its neutrons not nucleons